Substrate wetting and dewetting

The equilibrium situation which exists after a liquid drop is brought into contact with a smooth homogeneous substrate depends on the balance between adhesion and cohesion free energies involved. Three cases can be identified  

6 — PREPARATION OF ASYMMETRIC CERAMIC MEMBRANE SUPPORTS BY DIP-COATING 

The contact angle 0 above is the static or equilibrium contact angle and is a thermodynamically defined quantity as we will see below. 

The static contact angle is given by the Young (-Gibbs) equation (see for example Ref. [69])  

Similarly, in the case of wetting by a surfactant solution instead of pure liquid rtSLisgivenby 

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